Long story short my son bought a 2003 e500. After a few months of driving it the front brakes needed changed. So I changed the brakes, bled the system the old fashion way. I originally got little to no fluid but finally I got a good strong stream on both wheels. Put everything back together and I had a little pedal until I cranked the car and when I put it in drive I lost all brake pressure. Cut the car off pumped the brakes a few times and got pressure recranked and put in drive and again lost all pressure. Double checked everything which looks good. I do have the red brake alarm on the dash that screams constantly so I googled that and this is where I learn about the SBC system. So now I'm 2 1/2 hours away from the nearest dealership and 1 1/2 hrs from any shop that will look at it but doesn't specialize in Mercedes so they don't promise anything. Any ideas or tricks of the trade I could try? I'm currently stumped as I can work on just about anything car related without getting stressed out because it's like therapy to me. Any help would be greatly appreciated.

 

I would guess that when you pumped the brakes you went too far of a pedal stroke and ruined the seal in the master cylinder. The only solution is to replace the master cylinder and bleed all of the brakes properly.

 

That's better than most are telling me. Everyone else seems to think the sbc is trashed. So trying the master cylinder would be worth it? I have nice brake pedal pressure but only to the front driver side not the front passenger side. Front passenger is the only one I cannot get pressure to get to the brake itself. I have even taken the brakes back off, pushed the pistons back in and reinstalled. I properly bleed all the brakes with a scan tool but I have no pressure on the passenger front brake but the brake pistons will push out but just enough to let the pads almost touch the rotor but not quite enough. Just racking my brain as to why this side is giving me the issue. The dreaded red dash screen and constant beeping.

 

I'm not ruling out the SBC. What caught my attention was pumping the brakes after bleeding the brakes "the old fashioned way" which I assume is pumping the pedal and then opening the screw.

I always used a vacuum bleeder which is, in my experience, the best method. To do so, you must go around the vehicle RR, LR, RF, RL. Of course, start with a freshly bled master cylinder and all new DOT 4 fluid. You will have to wrap the bleeder screw threads with Teflon tape and use a securely fitting hose on the bleeder screw nipple. Vacuum bleeding is, in essence, pressure bleeding at about 14.7 psi atmospheric pressure. You will use 3-4 pints of brake fluid to bleed the system.

See how that goes.

 

I will give it a try. At this point I'm up for any options. Thank you very much

 

Well, with a new master cylinder and proper bleeding at all four wheels, you pretty much have eliminated any air in the lines. The only other issue is to cycle the ABS pump with the scan tool. After that, let us know if you have codes in that system.